1. Field of Invention
Various exemplary embodiments relate generally to an electronic device and, more particularly, to a semiconductor memory device and an operating method thereof.
2. Description of Related Art
Semiconductor memory devices are typically categorized into volatile memory devices and non-volatile memory devices.
Non-volatile memory devices operate at relatively slow write and read speeds, but they can retain stored data in the absence of a power supply. Therefore, non-volatile memory devices may be used to store data that needs to be retained regardless of power on/off conditions. Examples of non-volatile memory devices include Read Only Memory (ROM), Mask ROM (MROM), Programmable ROM (PROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, Phase-change Random Access Memory (PRAM), Magnetoresistive RAM (MRAM), Resistive RAM (RRAM) and Ferroelectric RAM (FRAM). Flash memories are categorized into NOR and NAND types.
Flash memories enjoy the advantages of both RAM and ROM. For example, flash memories may be freely programmed and erased similar to RAM. Similar to ROM, flash memories may retain stored data even without a power supply. Flash memories have been widely used as the storage media of portable electronic devices such as mobile phones, digital cameras, personal digital assistants (PDAs), and MP3 players.